I just learned this in science a month ago! Redi used a piece of meat in a jar and covered it with a cheesecloth. He got another jar of meat and left it open. He wanted to see if magots developed from flies or not. Luis Pasteur used an 'S' tube thingy and put broth inside and boiled it. Then he waited to see if broth fogged up because of dust or microorganisms. One tube was pointed upward so dust could get inside, and the other, downward. Hope this kindof explains this topic to you!
